Re: [patch 1/13] Qsort

[Matt Mackall]

On Sun, Jan 23, 2005 at 01:22:13PM +0100, Andreas Gruenbacher wrote:
> On Sunday 23 January 2005 06:32, Matt Mackall wrote:
> > Yes, indeed. Though I think even here, we'd prefer to use kmalloc
> > because gcc generates suboptimal code for variable-sized stack vars.
> 
> That's ridiculous. kmalloc isn't even close to whatever suboptimal
> code gcc might produce here. Also I'm not convinced that gcc
> generates bad code in the first place. The code I get makes perfect
> sense.

Fixed-sized slab-based kmalloc is O(1) (and pretty darn fast). If we
take a constant overhead for every local variable lookup in qsort,
that's O(n log n). Putting the stack vars last might fix that, but I
think it needs testing. I'll try it.

-- 
Mathematics is the supreme nostalgia of our time.
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